Appearances by Comic Book Creators!

Stan and Jack, from F4#10 (1962)

Stan, Jack and other Bullpenners from Fantastic Four #176. Check out the autographed Vision poster! (1975)

A statue of Jim Shooter, from Fantastic Four #229 (1981). I suspect this was part of Marvel’s effort to make Jim Shooter as much of a personality as Stan Lee, who himself had gone to Hollywood to try to sell and develop Marvel TV and movie properties.

Julius Schwartz, from Justice League #153 (1978). JLA had a whole alternate Earth where its creators existed, just like Marvel.
Ann Nocenti from Avengers #215 (1982). A cameo by one of Marvel’s first female writer/editors, and one of its most controversial.

Al Milgrom, the artist, draws himself into Avengers #237 (1983). I can’t find any relevant significance to the name “Sikorski.” Maybe Al was really Polish? Anyway, he became an ongoing character–but this was his first appearance.